Mine have velcro too. I believe, but do not quote me, that velcro on the bottom is a pretty common way to keep cushions from moving.
Also, something to think about, assuming you have cushions currently. I took in my V berth, where there was two, and made it on bigger one. Added a cushion I did not have for the saloon, and IIRC, in the aft stateroom, a spot where there was two med and on smaller, I made into two cushions also. It made getting under these area's actually easier.
Actually, my V Birth had two cushions, side by side. I'm going to convert that to two smaller triangle ones forward with one wider but less deep one aft. That's because I have a locker in the aft part of the V Birth I want to get into easily, but before it required removing both cushions from the V Birth - what a pain! This should be easier, with just that smaller aft cushion needing to be moved.
Other than that, there really are no other spaces where breaking the cushions into more than one would help. But actually, its worth thinking about, just to make getting the cushions on and off the boat easier, should I want to, say for winter storage.
Thanks for the suggestion!